The present invention relates to a vane machine, especially a vane pump or vane motor, including a housing and a mechanism located in a recess or compartment in the housing, wherein the mechanism comprises a rotatable rotor provided with a plurality of radial slots distributed around its circumference, a plurality of vanes each having a first end and a second end opposite the first end and being guided movably in one of the radial slots to form a compression chamber in that radial slot bounded by walls of that radial slot. The first end of the vanes is located inside that radial slot and the second end is located outside the radial slot and bears on a mechanism wall which moves the vane in the slot during a revolution of the rotor to simultaneously force a volume change in the compression chamber and at least one first compensation duct is provided for a pressurized medium supplied to the compression chambers so that a pressurized medium flows from an inlet connector to an outlet connector of the vane machine.
This type of vane machine is already generally known and it is recognized that the vanes can be prevented from lifting off the vane-motion-producing wall by applying system pressure to the interior ends of the vanes.
The application of the system pressure to the vanes has the disadvantage that the effective hydraulic force on the vanes is limited to the maximum possible system pressure for the vane machine. Comparatively high system pressure produces friction between the outer edges of the vanes and the wall acting to move the vanes in their radial slots, which exceeds the load limit for the materials of both components. Wear and thus a shortening of the lifetime of the vane machine results.
In the vane machine disclosed in German Patent Application DE-OS 1 728 268 the pressure on the vanes is lowered to a constant intermediate pressure by means of a pressure regulator, as soon as the vanes enter their suction or vacuum stage. The pressure regulator, which has a gate valve cooperating with a valve spring so as to react comparatively slowly to changes in the pressure conditions, is integrated in the housing of the vane machine. Its operating conditions are thereby extended to higher system pressures. Generally the intermediate pressure is adjusted for only one operating point of the vane machine. This operating point may wander or vary only slightly before disadvantageous friction, wear or poor performance result.